1. Field of the Invention
This invention relates to structure for guiding a submersible pump along an upright axis toward and away from a lowermost position wherein the pump outlet is in adjacent, fluid-communicating relationship with an inlet of a stationary discharge pipe. The guide structure includes a stationary, upright, transversely I-shaped guide rail and a wire-like connector coupling the pump to the rail, and the connector is configured to clean the rail during movement of the pump to minimize binding. The invention also is directed to an alignment means for maintaining an outlet flange of the pump in spaced disposition from an inlet flange of the discharge pipe when the pump unit is in its lowermost position so that seizing of the two flanges is substantially precluded. A pair of outwardly extending, transversely D-shaped arms coupled to the pump flange engage inclined, marginal edge portions of two elements which flank the discharge pipe inlet flange.
2. Description of the Prior Art
A variety of means have been proposed in the past for lifting submersible pump units out of a pump basin, tank or the like so that the pump can be serviced or replaced when necessary. Oftentimes, guide structure is provided for directing movement of the pump unit along an upright axis toward and away from a lowermost position wherein an outlet flange of the pump unit is in adjacent, face-to-face fluid-communicating relationship with an inlet flange of a stationary discharge pipe that is commonly secured to the walls of the tank or basin. One principal function of such lifting means and guide structures is to reduce the likely necessity of employing a diver to descend into the liquid for manual connection of the pump to the discharge pipe.
In the past, certain submersible pump guide structures have comprised a relatively stiff, vertical guide rail that is fixed to a bottom of a tank or basin or other structure therein, and the guide structures further include a connector that is slidably received on the guide rail and coupled to a pump unit. One example of such guide structure is shown in U.S. Pat. No. 3,797,970 to Blum, and takes the form of an elongated, generally cylindrical connector that is slidably received around a cylindrical guide tube. Unfortunately, it has been found that the sliding interconnection between the cylindrical connector and the guide tube shown in U.S. Pat. No. 3,797,970 inherently provides a relatively large amount of slidably engaging surface areas that are subject to frictional forces which resist attempts to lift the pump from the basin. Additionally, if the lifting device or hoist is not in precise vertical alignment with the center of gravity of the pump unit, the cylindrical connector will bind as the pump is raised. Moreover, the annular gap between the connector and the guide tube shown in U.S. Pat. No. 3,797,970 creates a relatively large chamber for entrapment of particulates and debris that are normally present in sewage and other waste waters, and these particulates further cause binding between the connector and the guide tube to resist lifting of the pump. Any corrosion in the interior surfaces of the connector or the outer surfaces of the guide tube will also undesirably increase the amount of friction encountered during removal of the pump from the basin.
Other types of guide structures comprising upright, cylindrical guide tubes in combination with sliding, cylindrically surfaced connectors coupled to a pump unit are shown in U.S. Pat. Nos. 4,308,000 dated Dec. 29, 1981, 4,060,345 dated Nov. 29, 1977, and 3,771,915 dated Nov. 13, 1973. The guide structure shown in the last mentioned patent, U.S. Pat. No. 3,771,915 shows a pump unit secured to a carrier having two transverse bars formed to complementally engage a pair of spaced, upright guide tubes. Unfortunately, the use of two of such upright guide tubes can increase the amount of surface areas exposed to friction and further a dual guide tube arrangement is more subject to binding than a single guide tube apparatus when the hoist is not in proper, vertical alignment with the pump unit.
U.S. Pat. No. 3,771,914 dated Nov. 13, 1973 is directed to a guide structure having two spaced guide bars which are generally I-shaped in transverse configuration. However, the pump connector shown in U.S. Pat. No. 3,771,914 which slides along the upright guide bars resembles a collar or sleeve that is believed to provide an excessive amount of interengageable surface areas subject to frictional forces, in similar manner to cylindrical connectors.
It is also known that certain of the prior art guide structures enable the pump unit to be advantageously tilted during lifting of the same, in an attempt to avoid wedging effects between the slide connector and the guide tubes. An example of this type of device is shown in U.S. Pat. No. 4,324,531 dated Apr. 13, 1982 and comprises a bipartite slide having two upper and two lower projections which complementally slide along two spaced upright guide tubes, but each of these four projections contributes an undesirable amount of surface area for binding between the shiftable slide and the stationary guide tubes.
Those who are knowledgeable in the art will also readily recognize the fact that prolonged engagement of a flat face of an outlet flange with a flat face of a stationary discharge pipe will often corrode the flange faces and "seize" the flanges together. While corrosion can occur even with relatively clean liquids, this problem is highly aggravated in various waste water environments. Thus, in some instances, it has been found desirable to maintain the flanges in slightly spaced relationship, and utilize a flexible seal which is hydraulically forced into sealing engagement with the adjacent flange when the pump is in service. An example of a hydraulic seal is shown in U.S. Pat. No. 3,592,564, dated July 13, 1971 and assigned to the assignee of the present invention.
The aforementioned U.S. Pat. No. 4,308,000 has guide structure which includes a means for shifting the pump unit laterally as it approaches its lowermost position in an effort to move an outlet flange of the pump toward a position of adjacent, spaced relationship with an inlet flange of a stationary discharge pipe. The guide structure disclosed in U.S. Pat. No. 4,308,000 includes a spaced pair of vertical guide tubes that are slidably engageable with complemental, semicylindrical flanges connected to the rear of the pump, whereas the pump outlet flange extends outwardly from the front of the pump. As the pump unit of this reference descends to its lowermost position, the sliding connector flanges engage an inclined, upper cammed face of collars that are secured to the guide tubes in order to attempt lateral shifting of the pump unit toward a position wherein the pump flange is adjacent the outlet pipe flange.
However, it is believed that the guide apparatus shown in U.S. Pat. No. 4,308,000 is somewhat deficient in assuring that the pump flange is in proper spaced disposition from the discharge pipe flange when the pump unit is in its lowermost position. For one thing, the collars having camming surfaces are adjustably coupled to the guide tubes which are, in turn, spaced in remote relationship to the two flanges so that the spacing between the flanges is difficult to repeatedly attain with a reasonable degree of precision, a problem that can easily remain unnoticed in the submerged environment of waste water pumps. Secondly, any accidental deflection of the guide tubes, as perhaps would be caused during raising or lowering of the pump, will adversely affect the position of the flanges and the spacing therebetween. Finally, no means is provided in U.S. Pat. No. 4,308,000 for positively retaining the two flanges in spaced disposition, except as would otherwise inherently occur when the rear surface of the semicircular connector flanges engages a rear portion of the guide tubes, an occurrence that is unlikely to occur if the semicircular surfaces of the flanges are of a diameter large enough to enable a free, loose sliding fit as the pump unit is raised or lowered.
As can be appreciated from the foregoing, it would be a desirable advance in the field of submersible pump technology if a guide structure was provided for raising and lowering pumps from basins, tanks or the like with a minimum of friction and binding between engaging parts. Additionally, it would be desirable to provide a means for positively maintaining a pump outlet flange a predetermined horizontal spacing from a discharge pipe flange and, at the same time, provide horizontal alignment between the flanges so that discharge of fluids by the pump is not hindered by misaligned flanges. Such a guide structure would preferably allow tilting of the pump during raising or lowering thereof, but would also bias the pump back toward a position relative to horizontal so that the pump flange is in flat, parallel, face-to-face relationship with the discharge pipe flange when the pump unit reaches its lowermost position for subsequent pumping of fluids.